The ledger is integral to Shillingcoin as a sequential record of all transactions and in Cryptocoin terminology known as the block chain. It records coin ownership at present and at all points in the past. Approximately every ten minutes a bundle of transactions, called a block, is added to the systemwide block chain. A reward of 50 coins per block added to the block chain is given to users maintaining the ledger. By keeping a record of all transactions, the block chain prevents double-spending, a problem particular to digital money.